Bulk bag with lift loops

ABSTRACT

A bulk bag and method of making the bulk bag uses lift hoops that are securely linked to eyelets of lift straps that are attached to a bulk bag body so that the bulk bag can be lifted by the lift hoops. The bulk bag body includes a top portion, a bottom portion and a side portion. The lift straps may be attached to the bulk bag body such that at least portions of the lift straps extend along the side portion of the bulk bag body at an angle from the top portion of the bulk bag body to the bottom portion of the bulk bag body.

CROSS REFERENCE TO RELATED APPLICATION

This application is entitled to the benefit of U.S. Provisional Patent Application Ser. No. 61/759,335, filed on Jan. 31, 2013, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Bulk bags are used for the transportation of bulk materials. Bulk bags are usually fabricated by stitching or sewing polypropylene woven fabric. Lift straps are typically sewn onto the body fabric so that the bulk bag can be lifted by a forklift or other equipment.

Lift straps of a bulk bag are commonly made of either multifilament or monofilament materials. Multifilament straps are generally softer and easier to handle by workers to place the straps onto hooks of a filling station equipment. The multifilament straps drop down naturally by gravity when not in use. Therefore, the multifilament straps do not interference with other machinery when the bulk bag is moved or transported.

A disadvantage of multifilament straps lies in their incompatibility in elasticity with the polypropylene body fabric of the bulk bag. When the bulk bag is lifted by its multifilament straps, the highly elastic multifilament straps stretch out more than the polypropylene body fabric, which may result in the breakage of the sewing stitches and/or the body fabric at the strap attachment areas. Another disadvantage is that multifilament straps are also more expensive than monofilament straps.

In contrast, monofilament straps have an elasticity that is close to the polypropylene body fabric. Therefore, when the monofilament straps of a bulk bag are lifted and stretched, the monofilament straps are more compatible with the body fabric.

A disadvantage of monofilament straps is that the monofilament strap is more stiff and harder to use when being placed onto the filling station hooks. The monofilament straps also stand up when not in use, which is not desirable in many situations since the upright straps can cause interference with the machinery around the bulk bags.

SUMMARY OF THE INVENTION

A bulk bag and method of making the bulk bag uses lift hoops that are securely linked to eyelets of lift straps that are attached to a bulk bag body so that the bulk bag can be lifted by the lift hoops. The bulk bag body includes a top portion, a bottom portion and a side portion. The lift straps may be attached to the bulk bag body such that at least portions of the lift straps extend along the side portion of the bulk bag body at an angle from the top portion of the bulk bag body to the bottom portion of the bulk bag body.

A bulk bag in accordance with embodiments of the invention comprises a bulk bag body that includes a top portion, a bottom potion and a side portion, a plurality of lift straps with eyelets attached to the bulk bag body, and a plurality of lift hoops secured on the eyelets of the lift straps. Each lift hoop is securely linked through one of the eyelets of the lift straps so that the bulk bag can be lifted by the lift hoops. The lift straps may be monofilament lift straps and the lift hoops may be multifilament lift straps.

A method of making a bulk bag in accordance with embodiments of the invention comprises constructing a bulk bag body that includes a top portion, a bottom potion and a side portion, and attaching a plurality of lift straps with eyelets to at least one component of the bulk bag body, including securing a plurality of lift hoops secured to the eyelets of the lift straps such that each lift hoop is securely linked through one of the eyelets of the lift straps so that the bulk bag can be lifted by the lift hoops.

Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrated by way of example of the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a bulk bag in accordance with an embodiment of the invention.

FIG. 2 is a bottom view of the bulk bag shown in FIG. 1.

FIG. 3 is diagram illustrating lift straps that are attached to a bulk bag body in accordance with another embodiment of the invention.

FIG. 4 is a partial perspective view of a bulk bag in accordance with another embodiment of the invention.

FIG. 5 is a partial perspective view of a bulk bag in accordance with another embodiment of the invention.

DETAILED DESCRIPTION

It will be readily understood that the components of the embodiments as generally described herein and illustrated in the appended figures could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of various embodiments, as represented in the figures, is not intended to limit the scope of the present disclosure, but is merely representative of various embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by this detailed description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussions of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize, in light of the description herein, that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.

Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the indicated embodiment is included in at least one embodiment of the present invention. Thus, the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

With reference to FIGS. 1 and 2, a bulk bag 100 in accordance with an embodiment of the invention is described. As best shown in FIG. 1, the bulk bag 100 includes a bulk bag body 102 that is formed of a top portion 104, a bottom portion 106 and a side portion 108. In an embodiment, the bulk bag body 102 is made of polypropylene woven fabric or other suitable material. The bulk bag body 102 can be made of single layer of fabric or multiple layers of fabric. The bulk bag 100 further includes lift straps 110 that are attached onto the bottom and side portions 106 and 108 of the bulk bag body 102 so that the lift straps are attached to the outer surface of the bulk bag body, as shown in FIGS. 1 and 2. As an example, the lift straps 110 may be sewn onto the bulk bag body 102. In an embodiment, the lift straps 110 are made of monofilament material and have a similar elasticity with the bulk bag body 102. As used herein, having a similar elasticity with the bulk bag body means having an elasticity that is within 10 percent of the elasticity of the bulk bag body.

In order to avoid the problem of conventional monofilament lift straps sticking up above the bulk bag and causing interference with nearby machinery when the lift straps are not in use, a small eyelet 112 is formed at each top corner of the bulk bag 100 using the lift straps 110. Each eyelet 112 is flat with, under, or slightly above the top portion 104 of the bulk bag body 102. If the eyelet 112 is slightly above the top portion 104 of the bulk bag body 102, the height of the eyelet 112 is generally within 2 times of the width of the lift straps 110 so that the eyelet will not cause interference with nearby machinery. To serve as the primary lifting mechanism for the bulk bag 100, an enclosed lift loop 114 is securely linked through each eyelet 112. In an embodiment, the loops 114 are made of multifilament material. However, the lift loops 114 may be made of monofilament material. The lift loops 114 drop down naturally when not in use so that the lift loops do not interfere with nearby machinery.

As illustrated in FIG. 1, the lift straps 110 are angled along the side portion 108 of the bulk bag body 102. The lift straps 110 being angled means that the straps are away from a totally vertical orientation, as shown in FIG. 1. The upper ends of the straps 110 are located at the top corners of the bulk bag 100 to facilitate filling operation requirements. However, the lower ends of the straps 110 are located close to the middle of the bulk bag body 102 away from the bottom corners of the bulk bag 100 to form a double crossed (e.g., “#”) shape or other similar shapes at the bottom portion 106 of the bulk bag body 102, as shown in FIG. 2, so that the straps at the bottom of the bulk bag 100 bears the maximum amount of the load and the bottom portion of the bulk bag body bears the minimum amount of the load.

The whole length of the angled lift straps 110 may be attached or sewn onto the bulk bag body 102. However, in other embodiments, the whole length of the angled lift straps 110 are not attached or sewn onto the bulk bag body 102. Rather, the angled lift straps 110 are attached or sewn at selected locations, such as locations 116 near the top corners of the bag 100, as shown in FIG. 1, and locations 118 at the bottom portion of the bulk bag body 102, as shown in FIG. 2, in order to uniform the loading when the bulk bag 100 is lifted. The angled lift straps 110 together with the corner eyelets 112 and bottom double crossed support provides a bag that has corner lift loops to facilitate the filling machine requirements and has an extremely strong bottom for heavy duty load, such as UN certified bags.

In an embodiment, the lift straps 110 at the locations 116 are vertical, as illustrated in FIG. 1. The lift straps 110 below the locations 116 are angled. However, in another embodiment, the lift straps 110 are angled at and below the locations 116, as illustrated in FIG. 3.

In an embodiment, the lift straps 110 may be pre-stretched lift straps to further increase the load capacity for heavy duty requirement. In addition, the length of the lift straps 110 when measured from the top of the bulk bag 100 to the bottom of the bulk bag is 3%-15% shorter than the corresponding body fabric that is under the lift strap. When lifting bulk bags holding heavy load, the lift straps and the bulk bag body fabric will inevitably be stretched out. When the lift straps and the bulk bag body fabric have the same or similar elasticity and are stretched out by the same amount, the body fabric will start to break first since it is a weaker material. At the same time, the lift straps are still within their strength limit. By using the pre-stretched lift straps 110, when the bulk bag 100 is lifted under heavy load conditions, the lift straps are stretched out to bear the major load but the stretch on the bulk bag body 102 is much less. This prevents the breakage of the bulk bag body 102 and significantly increases the load capacity of the bulk bag.

In an embodiment, the bulk bag 100 may include an optional perimeter band 120 on the side portion of the bulk bag body 102 for added strength. The perimeter band 120 is attached to the bulk bag body 102 over the lift straps 110. The perimeter band 120 can be placed at the very top of the bulk bag body 102, as shown in FIG. 1, or the perimeter band 120 may be placed slight below the top of the bulk bag body, as shown in FIG. 4. As advantage of the configuration shown in FIG. 4 is that the eyelets 112 can be completely below the top of the bulk bag body 102. FIG. 5 shows a similar arrangement where the eyelets 112 are below the top of the bulk bag body 102 except that the perimeter band 120 is not used.

The bulk bag 100 further includes a fill spout 122, which is shown in

FIGS. 1, 4 and 5, and a discharge spout 124, which is shown in FIG. 2. The fill spout 122 and/or discharge spout 124 may use one or more wire ties to close the spouts, such as a wire tie 128 for the fill spout 122, which is illustrated in FIGS. 1, 4 and 5. In other embodiments, the fill spout 122 may be replaced with an open top or duffle top configuration. In an embodiment, a liner 126 may be placed inside of the bulk bag 100. The liner 128 can be a straight tube or a form fit shape where it has the same geometry as the bulk bag 100. The liner 128 can be free from the bulk bag 100 or it can be attached to the bulk bag at various places.

The bulk bag body 102 can be constructed by sewing pieces of fabric together. There are several methods of constructing the bulk bag body 102. The first method involves using a tubular fabric, which serves as the side portion 108 of the bulk bag body. The top portion 104 and the bottom portion 106 are sewn onto the tubular fabric to form the bulk bag body 102. The second method involves using a U-shaped panel of fabric, which forms the bottom portion 106 and front and back panels of the bulk bag body 102. Two separate pieces are sewn to the U-shaped fabric to form the left and right panels of the bulk bag body 102. The third method involves using six pieces of fabric, which form the top, the bottom and the four sides of the bulk bag body 102. Other methods of constructing the bulk bag body 102 are possible.

Depending on the method used to construct the bulk bag body 102, the way to attach or sew the lift straps 110 onto the bulk bag body can vary. Typically, the lift straps 110 need to be attached or sewn onto the bottom fabric, i.e., the bottom portion 106 of the body 102, first and then the tubular fabric or other panels of the body can be added. The top portion 104 is normally attached or sewn on after the side and bottom portions of the body have been formed. There can be other ways to attach the different components of the bulk bag 100 together as long as they can achieve the final design of the bulk bag.

When filling the bulk bag 100, the lift loops 114 of the bulk bag are placed onto the filling machine hooks to hang the bulk bag. The fill spout 122 is connected to the spout of the filling machine. After filling the bulk bag 100, the lift loops 114 of the bulk bag are released from the filling machine hooks either automatically or manually. The lift loops 114 drop down naturally when they are not in use. When lifting the bulk bag 100 for transportation, the bulk bag is lifted up by the lift loops. The weight of the content in the bulk bag 100 stretches out the bulk bag body 102 and the lift straps 110. However, since the lift straps 110 have the same or similar elasticity as the bulk bag body 102, the lift straps stretch out by the same amount as the bulk bag body. Thus, the problem associated with the conventional multifilament types of lift straps where the lift straps stretch more than the body fabric and cause the body fabric to fail prematurely is avoided. Under heavier loads, the bulk bag body 102 and the lift straps 110 will be more stretched. The bulk bag body 102 will start to fail before the lift straps 110.

However, under this situation, the lift straps 110, which may be pre-stretched, will be bearing the majority of the load. Thus, the stretch on the bulk bag body 102 would be much less, which ensures that the bulk bag 100 has a much higher load capacity. The double crossed or similar shape of the straps 110 at the bottom of the bulk bag supports the bottom portion 106 of the body 102 well to avoid breakage on the bottom fabric. Therefore, the bulk bag 100 can be used in very high load situations. The bulk bag 100 can be used where UN bags are needed for the transportation of dangerous materials.

Although specific embodiments of the invention have been described and illustrated, the invention is not to be limited to the specific forms or arrangements of parts so described and illustrated. The scope of the invention is to be defined by the claims appended hereto and their equivalents. 

What is claimed is:
 1. A bulk bag comprising: a bulk bag body that includes a top portion, a bottom potion and a side portion; a plurality of lift straps with eyelets attached to the bulk bag body; and a plurality of lift hoops secured on the eyelets of the lift straps, each lift hoop being securely linked through one of the eyelets of the lift straps so that the bulk bag can be lifted by the lift hoops.
 2. The bulk bag of claim 1 wherein the lift straps are made of monofilament material.
 3. The bulk bag of claim 2 wherein the lift hoops are made of multifilament material.
 4. The bulk bag of claim 2 wherein the bulk bag body is made of a polypropylene woven fabric.
 5. The bulk bag of claim 2 wherein the lift straps have a similar elasticity as the bulk bag body.
 6. The bulk bag of claim 1 wherein at least portions of the lift straps extend along the side portion of the bulk bag body at an angle from the top portion of the bulk bag body to the bottom portion of the bulk bag body.
 7. The bulk bag of claim 6 wherein the lifts straps extend along the bottom portion of the bulk bag body to support the bulk bag body.
 8. The bulk bag of claim 7 wherein the lifts straps extend along the bottom portion of the bulk bag body to form a double crossed shape.
 9. The bulk bag of claim 1 wherein the eyelets of the lifts straps are located at top corners of the bulk bag body.
 10. The bulk bag of claim 1 further comprising a perimeter band attached to the bulk bag body over the lift straps.
 11. A method of making a bulk bag, the method comprising: constructing a bulk bag body that includes a top portion, a bottom potion and a side portion; and attaching a plurality of lift straps with eyelets to at least one component of the bulk bag body, including securing a plurality of lift hoops secured to the eyelets of the lift straps such that each lift hoop is securely linked through one of the eyelets of the lift straps so that the bulk bag can be lifted by the lift hoops.
 12. The method of claim 11 wherein the lift straps are made of monofilament material.
 13. The method of claim 12 wherein the lift hoops are made of multifilament material.
 14. The method of claim 12 wherein the bulk bag body is made of a polypropylene woven fabric.
 15. The method of claim 11 wherein the attaching the plurality of lift straps includes attaching the plurality of lift straps with the eyelets to at least one component of the bulk bag body such that at least portions of the lift straps extend along the side portion of the bulk bag body at an angle from the top portion of the bulk bag body to the bottom portion of the bulk bag body.
 16. The method of claim 15 wherein the attaching the plurality of lift straps includes attaching the plurality of lift straps with the eyelets to at least one component of the bulk bag body bag such that the lift straps extend along the bottom portion of the bulk bag body to support the bulk bag body.
 17. The method of claim 16 wherein the attaching the plurality of lift straps includes attaching the plurality of lift straps with the eyelets to at least one component of the bulk bag body such that the lifts straps extend along the bottom portion of the bulk bag body to form a double crossed shape.
 18. The method of claim 11 further comprising attaching a perimeter band to the side portion of the bulk bag body over the lift straps.
 19. A bulk bag comprising: a bulk bag body that includes a top portion, a bottom potion and a side portion; a plurality of monofilament lift straps with eyelets attached to the bulk bag body; and a plurality of multifilament lift hoops secured on the eyelets of the monofilament lift straps, each multifilament lift hoop being securely linked through one of the eyelets of the monofilament lift straps so that the bulk bag can be lifted by the multifilament lift hoops.
 20. The bulk bag of claim 19 wherein at least portions of the monofilament lift straps extend along the side portion of the bulk bag body at an angle from the top portion of the bulk bag body to the bottom portion of the bulk bag body and the monofilament lift straps extend along the bottom portion of the bulk bag body to form a double crossed shape. 